The TSP 800 Star Printer is the most difficult printer in the world. Fortunately for us, it won't lose its usefulness on July 1, 2017, because of stupid MaineCare regulations where we cannot print them a script on regular paper for Melatonin or Vitamin C or amoxicillin like we can with someone who is self-pay or has private insurance.
Without seeing a jpg or png file it is difficult to tell. But, I have used the Star Printer for over ten years, and I have seen a lot of its fonts.
The printer likes to print the entire script on one line. So, if I print a relatively short script, it uses the same font as the rest of the script. If I print a somewhat longer script, the font comes out about 0.0005 font. A little bit of an exaggeration, but it is definitely legible. It never gets any smaller than that.